Since the end of World War II, the automobi le industry of Japan has marvelously developed, and the country has proved to be one of the dominant producers in this field of production next to the U. S. A., and this has been playing a very important role in the whole manufacturing industries in Japan. The object of this treatise is, first, to clarify the producing areas of automobile industry in Japan and to formulate the functioning system which exists among the areas, and secondly, to analyse the structure and function of the major producing areas, i. g. Keihin and Chukyo. 1. About 45% of the whole automobile production in Japan comes from the Keihin area (Tokyo, Kanagawa, Saitama), where such main factories of car makers as Nissan, Isuzu, Honda, and Hino are located, and 30% from Chukyo area (Aichi, Gif u), where Toyota and Mitsu-bishi, are located. In these two areas, many parts and body makers are concentrated along with these big car makers, forming the two major producing areas in Japan. In addition to these two major producing areas, there form such five minor producingg areas as Osaka where Dai-hatsu, Hiroshima where Mazda, Gunma where Subaru, Shizuoka (Hamamatsu) where Suzuki, and Okayama (Mizushima) where Mitsubishi are respectively located. Both major and minor producing areas are, when examined according to certain indices, to be characterized as follows: First, the former areas, above all the Keihin area, produce a great variety of cars and parts, while the latter produce only a few kinds of smaller typed cars and parts. Secondly, the automobile industry in Japan is generally based on the other machine industries. And in the major areas, especially in the Keihin area, it has developed based on the numerous proce-eding industries since the prewar days, having started in the Meiji Era. While, in the minor producing areas except Osaka, it has developed based on only a few of such pre-existing industry as weaving machine and airplane manufactures, and it came into being for the first time after the War in the areas concerned. Thirdly, when the fact that the automobile is produced by assemblying of various kinds of parts, and the fact that the relationship exists between the car makers and the parts makes are taken into consideration it is to be said that an areal system of production which takes the initiatives for the others exists centering on both the Keihin and the Chukyo areas. 2. In the keihin area, the greatest of the major producing areas, most of the plants are concentrated in the Jonan district, from Tokyo Tower to the Port of Yokohama, forming the core area of distribution. Racently most of both car makers and part makers of large scale have been moving into the outskirts of Keihin area, and the leading status of the Jonan district is being declined, but it is a solid fact that there still exists a huge production unit formed by the accumulation of various types of parts makers, connected tightly and functionally in the form of subcontract with abundant fundamental industries as casting, gilding, pressing, and so on, most of which have been accumulated for a long time and playing an important role of ‘common root’, for every machine production. In other words, the development of automobile production in the Keihin area is maintained on the basis of accumulation of technique centering the Janan district. In the Chukyo area, there are two producing centers, namely Toyota and Nagoya districts. In the Toyota district, there is the Toyota Company which is one of the top car makers in Japan, and large scale parts makers, connected with the Toyota Company, form one of the typical single industry cities in Japan. In the Nagoya district, many parts makers are concentrated to-gether with fundamental industries, and they form the base of production system of the Chikyo area.